diff --git a/Include/Python.h b/Include/Python.h
index 1feb153..bf1ca6c 100644
--- a/Include/Python.h
+++ b/Include/Python.h
@@ -111,6 +111,7 @@
 #include "codecs.h"
 #include "pyerrors.h"
 
+#include "coreconfig.h"
 #include "pystate.h"
 #include "context.h"
 
diff --git a/Include/coreconfig.h b/Include/coreconfig.h
new file mode 100644
index 0000000..4401729
--- /dev/null
+++ b/Include/coreconfig.h
@@ -0,0 +1,318 @@
+#ifndef Py_PYCORECONFIG_H
+#define Py_PYCORECONFIG_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+#ifndef Py_LIMITED_API
+typedef struct {
+    const char *prefix;
+    const char *msg;
+    int user_err;
+} _PyInitError;
+
+/* Almost all errors causing Python initialization to fail */
+#ifdef _MSC_VER
+   /* Visual Studio 2015 doesn't implement C99 __func__ in C */
+#  define _Py_INIT_GET_FUNC() __FUNCTION__
+#else
+#  define _Py_INIT_GET_FUNC() __func__
+#endif
+
+#define _Py_INIT_OK() \
+    (_PyInitError){.prefix = NULL, .msg = NULL, .user_err = 0}
+#define _Py_INIT_ERR(MSG) \
+    (_PyInitError){.prefix = _Py_INIT_GET_FUNC(), .msg = (MSG), .user_err = 0}
+/* Error that can be fixed by the user like invalid input parameter.
+   Don't abort() the process on such error. */
+#define _Py_INIT_USER_ERR(MSG) \
+    (_PyInitError){.prefix = _Py_INIT_GET_FUNC(), .msg = (MSG), .user_err = 1}
+#define _Py_INIT_NO_MEMORY() _Py_INIT_USER_ERR("memory allocation failed")
+#define _Py_INIT_FAILED(err) \
+    (err.msg != NULL)
+
+#endif   /* !defined(Py_LIMITED_API) */
+
+
+typedef struct {
+    /* Install signal handlers? Yes by default. */
+    int install_signal_handlers;
+
+    /* If greater than 0: use environment variables.
+       Set to 0 by -E command line option. If set to -1 (default), it is
+       set to !Py_IgnoreEnvironmentFlag. */
+    int use_environment;
+
+    int use_hash_seed;      /* PYTHONHASHSEED=x */
+    unsigned long hash_seed;
+
+    const char *allocator;  /* Memory allocator: PYTHONMALLOC */
+    int dev_mode;           /* PYTHONDEVMODE, -X dev */
+
+    /* Enable faulthandler?
+       Set to 1 by -X faulthandler and PYTHONFAULTHANDLER. -1 means unset. */
+    int faulthandler;
+
+    /* Enable tracemalloc?
+       Set by -X tracemalloc=N and PYTHONTRACEMALLOC. -1 means unset */
+    int tracemalloc;
+
+    int import_time;        /* PYTHONPROFILEIMPORTTIME, -X importtime */
+    int show_ref_count;     /* -X showrefcount */
+    int show_alloc_count;   /* -X showalloccount */
+    int dump_refs;          /* PYTHONDUMPREFS */
+    int malloc_stats;       /* PYTHONMALLOCSTATS */
+    int coerce_c_locale;    /* PYTHONCOERCECLOCALE, -1 means unknown */
+    int coerce_c_locale_warn; /* PYTHONCOERCECLOCALE=warn */
+
+    /* Enable UTF-8 mode?
+       Set by -X utf8 command line option and PYTHONUTF8 environment variable.
+       If set to -1 (default), inherit Py_UTF8Mode value. */
+    int utf8_mode;
+
+    wchar_t *pycache_prefix; /* PYTHONPYCACHEPREFIX, -X pycache_prefix=PATH */
+
+    wchar_t *program_name;  /* Program name, see also Py_GetProgramName() */
+    int argc;               /* Number of command line arguments,
+                               -1 means unset */
+    wchar_t **argv;         /* Command line arguments */
+    wchar_t *program;       /* argv[0] or "" */
+
+    int nxoption;           /* Number of -X options */
+    wchar_t **xoptions;     /* -X options */
+
+    int nwarnoption;        /* Number of warnings options */
+    wchar_t **warnoptions;  /* Warnings options */
+
+    /* Path configuration inputs */
+    wchar_t *module_search_path_env; /* PYTHONPATH environment variable */
+    wchar_t *home;          /* PYTHONHOME environment variable,
+                               see also Py_SetPythonHome(). */
+
+    /* Path configuration outputs */
+    int nmodule_search_path;        /* Number of sys.path paths,
+                                       -1 means unset */
+    wchar_t **module_search_paths;  /* sys.path paths */
+    wchar_t *executable;    /* sys.executable */
+    wchar_t *prefix;        /* sys.prefix */
+    wchar_t *base_prefix;   /* sys.base_prefix */
+    wchar_t *exec_prefix;   /* sys.exec_prefix */
+    wchar_t *base_exec_prefix;  /* sys.base_exec_prefix */
+#ifdef MS_WINDOWS
+    wchar_t *dll_path;      /* Windows DLL path */
+#endif
+
+    /* If greater than 0, enable isolated mode: sys.path contains
+       neither the script's directory nor the user's site-packages directory.
+
+       Set to 1 by the -I command line option. If set to -1 (default), inherit
+       Py_IsolatedFlag value. */
+    int isolated;
+
+    /* If equal to zero, disable the import of the module site and the
+       site-dependent manipulations of sys.path that it entails. Also disable
+       these manipulations if site is explicitly imported later (call
+       site.main() if you want them to be triggered).
+
+       Set to 0 by the -S command line option. If set to -1 (default), it is
+       set to !Py_NoSiteFlag. */
+    int site_import;
+
+    /* Bytes warnings:
+
+       * If equal to 1, issue a warning when comparing bytes or bytearray with
+         str or bytes with int.
+       * If equal or greater to 2, issue an error.
+
+       Incremented by the -b command line option. If set to -1 (default), inherit
+       Py_BytesWarningFlag value. */
+    int bytes_warning;
+
+    /* If greater than 0, enable inspect: when a script is passed as first
+       argument or the -c option is used, enter interactive mode after
+       executing the script or the command, even when sys.stdin does not appear
+       to be a terminal.
+
+       Incremented by the -i command line option. Set to 1 if the PYTHONINSPECT
+       environment variable is non-empty. If set to -1 (default), inherit
+       Py_InspectFlag value. */
+    int inspect;
+
+    /* If greater than 0: enable the interactive mode (REPL).
+
+       Incremented by the -i command line option. If set to -1 (default),
+       inherit Py_InteractiveFlag value. */
+    int interactive;
+
+    /* Optimization level.
+
+       Incremented by the -O command line option. Set by the PYTHONOPTIMIZE
+       environment variable. If set to -1 (default), inherit Py_OptimizeFlag
+       value. */
+    int optimization_level;
+
+    /* If greater than 0, enable the debug mode: turn on parser debugging
+       output (for expert only, depending on compilation options).
+
+       Incremented by the -d command line option. Set by the PYTHONDEBUG
+       environment variable. If set to -1 (default), inherit Py_DebugFlag
+       value. */
+    int parser_debug;
+
+    /* If equal to 0, Python won't try to write ``.pyc`` files on the
+       import of source modules.
+
+       Set to 0 by the -B command line option and the PYTHONDONTWRITEBYTECODE
+       environment variable. If set to -1 (default), it is set to
+       !Py_DontWriteBytecodeFlag. */
+    int write_bytecode;
+
+    /* If greater than 0, enable the verbose mode: print a message each time a
+       module is initialized, showing the place (filename or built-in module)
+       from which it is loaded.
+
+       If greater or equal to 2, print a message for each file that is checked
+       for when searching for a module. Also provides information on module
+       cleanup at exit.
+
+       Incremented by the -v option. Set by the PYTHONVERBOSE environment
+       variable. If set to -1 (default), inherit Py_VerboseFlag value. */
+    int verbose;
+
+    /* If greater than 0, enable the quiet mode: Don't display the copyright
+       and version messages even in interactive mode.
+
+       Incremented by the -q option. If set to -1 (default), inherit
+       Py_QuietFlag value. */
+    int quiet;
+
+   /* If greater than 0, don't add the user site-packages directory to
+      sys.path.
+
+      Set to 0 by the -s and -I command line options , and the PYTHONNOUSERSITE
+      environment variable. If set to -1 (default), it is set to
+      !Py_NoUserSiteDirectory. */
+    int user_site_directory;
+
+    /* If equal to 0, enable unbuffered mode: force the stdout and stderr
+       streams to be unbuffered.
+
+       Set to 0 by the -u option. Set by the PYTHONUNBUFFERED environment
+       variable.
+       If set to -1 (default), it is set to !Py_UnbufferedStdioFlag. */
+    int buffered_stdio;
+
+#ifdef MS_WINDOWS
+    /* If greater than 1, use the "mbcs" encoding instead of the UTF-8
+       encoding for the filesystem encoding.
+
+       Set to 1 if the PYTHONLEGACYWINDOWSFSENCODING environment variable is
+       set to a non-empty string. If set to -1 (default), inherit
+       Py_LegacyWindowsFSEncodingFlag value.
+
+       See PEP 529 for more details. */
+    int legacy_windows_fs_encoding;
+
+    /* If greater than zero, use io.FileIO instead of WindowsConsoleIO for sys
+       standard streams.
+
+       Set to 1 if the PYTHONLEGACYWINDOWSSTDIO environment variable is set to
+       a non-empty string. If set to -1 (default), inherit
+       Py_LegacyWindowsStdioFlag value.
+
+       See PEP 528 for more details. */
+    int legacy_windows_stdio;
+#endif
+
+    /* --- Private fields -------- */
+
+    /* Install importlib? If set to 0, importlib is not initialized at all.
+       Needed by freeze_importlib. */
+    int _install_importlib;
+
+    /* Value of the --check-hash-based-pycs configure option. Valid values:
+
+       - "default" means the 'check_source' flag in hash-based pycs
+         determines invalidation
+       - "always" causes the interpreter to hash the source file for
+         invalidation regardless of value of 'check_source' bit
+       - "never" causes the interpreter to always assume hash-based pycs are
+         valid
+
+       Set by the --check-hash-based-pycs command line option.
+       If set to NULL (default), inherit _Py_CheckHashBasedPycsMode value.
+
+       See PEP 552 "Deterministic pycs" for more details. */
+    const char *_check_hash_pycs_mode;
+
+    /* If greater than 0, suppress _PyPathConfig_Calculate() warnings.
+
+       If set to -1 (default), inherit Py_FrozenFlag value. */
+    int _frozen;
+
+} _PyCoreConfig;
+
+#ifdef MS_WINDOWS
+#  define _PyCoreConfig_WINDOWS_INIT \
+        .legacy_windows_fs_encoding = -1, \
+        .legacy_windows_stdio = -1,
+#else
+#  define _PyCoreConfig_WINDOWS_INIT
+#endif
+
+#define _PyCoreConfig_INIT \
+    (_PyCoreConfig){ \
+        .install_signal_handlers = 1, \
+        .use_environment = -1, \
+        .use_hash_seed = -1, \
+        .faulthandler = -1, \
+        .tracemalloc = -1, \
+        .coerce_c_locale = -1, \
+        .utf8_mode = -1, \
+        .argc = -1, \
+        .nmodule_search_path = -1, \
+        .isolated = -1, \
+        .site_import = -1, \
+        .bytes_warning = -1, \
+        .inspect = -1, \
+        .interactive = -1, \
+        .optimization_level = -1, \
+        .parser_debug= -1, \
+        .write_bytecode = -1, \
+        .verbose = -1, \
+        .quiet = -1, \
+        .user_site_directory = -1, \
+        .buffered_stdio = -1, \
+        _PyCoreConfig_WINDOWS_INIT \
+        ._install_importlib = 1, \
+        ._frozen = -1}
+/* Note: _PyCoreConfig_INIT sets other fields to 0/NULL */
+
+
+#ifndef Py_LIMITED_API
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_Read(_PyCoreConfig *config);
+PyAPI_FUNC(void) _PyCoreConfig_Clear(_PyCoreConfig *);
+PyAPI_FUNC(int) _PyCoreConfig_Copy(
+    _PyCoreConfig *config,
+    const _PyCoreConfig *config2);
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_InitPathConfig(_PyCoreConfig *config);
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetPathConfig(
+    const _PyCoreConfig *config);
+PyAPI_FUNC(void) _PyCoreConfig_GetGlobalConfig(_PyCoreConfig *config);
+PyAPI_FUNC(void) _PyCoreConfig_SetGlobalConfig(const _PyCoreConfig *config);
+PyAPI_FUNC(const char*) _PyCoreConfig_GetEnv(
+    const _PyCoreConfig *config,
+    const char *name);
+PyAPI_FUNC(int) _PyCoreConfig_GetEnvDup(
+    const _PyCoreConfig *config,
+    wchar_t **dest,
+    wchar_t *wname,
+    char *name);
+#endif
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_PYCORECONFIG_H */
diff --git a/Include/internal/pystate.h b/Include/internal/pystate.h
index e041d37..ef83af5 100644
--- a/Include/internal/pystate.h
+++ b/Include/internal/pystate.h
@@ -72,6 +72,12 @@
     const _PyCoreConfig *core_config);
 PyAPI_FUNC(void) _PyPathConfig_ClearGlobal(void);
 
+PyAPI_FUNC(void) _Py_wstrlist_clear(
+    int len,
+    wchar_t **list);
+PyAPI_FUNC(wchar_t**) _Py_wstrlist_copy(
+    int len,
+    wchar_t **list);
 PyAPI_FUNC(_PyInitError) _Py_wstrlist_append(
     int *len,
     wchar_t ***list,
diff --git a/Include/pylifecycle.h b/Include/pylifecycle.h
index c58c7ec..4965d7c 100644
--- a/Include/pylifecycle.h
+++ b/Include/pylifecycle.h
@@ -7,36 +7,6 @@
 extern "C" {
 #endif
 
-#ifndef Py_LIMITED_API
-typedef struct {
-    const char *prefix;
-    const char *msg;
-    int user_err;
-} _PyInitError;
-
-/* Almost all errors causing Python initialization to fail */
-#ifdef _MSC_VER
-   /* Visual Studio 2015 doesn't implement C99 __func__ in C */
-#  define _Py_INIT_GET_FUNC() __FUNCTION__
-#else
-#  define _Py_INIT_GET_FUNC() __func__
-#endif
-
-#define _Py_INIT_OK() \
-    (_PyInitError){.prefix = NULL, .msg = NULL, .user_err = 0}
-#define _Py_INIT_ERR(MSG) \
-    (_PyInitError){.prefix = _Py_INIT_GET_FUNC(), .msg = (MSG), .user_err = 0}
-/* Error that can be fixed by the user like invalid input parameter.
-   Don't abort() the process on such error. */
-#define _Py_INIT_USER_ERR(MSG) \
-    (_PyInitError){.prefix = _Py_INIT_GET_FUNC(), .msg = (MSG), .user_err = 1}
-#define _Py_INIT_NO_MEMORY() _Py_INIT_USER_ERR("memory allocation failed")
-#define _Py_INIT_FAILED(err) \
-    (err.msg != NULL)
-
-#endif
-
-
 PyAPI_FUNC(void) Py_SetProgramName(const wchar_t *);
 PyAPI_FUNC(wchar_t *) Py_GetProgramName(void);
 
@@ -56,16 +26,6 @@
     const _PyCoreConfig *);
 PyAPI_FUNC(int) _Py_IsCoreInitialized(void);
 
-PyAPI_FUNC(_PyInitError) _PyCoreConfig_Read(_PyCoreConfig *config);
-PyAPI_FUNC(void) _PyCoreConfig_Clear(_PyCoreConfig *);
-PyAPI_FUNC(int) _PyCoreConfig_Copy(
-    _PyCoreConfig *config,
-    const _PyCoreConfig *config2);
-PyAPI_FUNC(_PyInitError) _PyCoreConfig_InitPathConfig(_PyCoreConfig *config);
-PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetPathConfig(
-    const _PyCoreConfig *config);
-PyAPI_FUNC(void) _PyCoreConfig_SetGlobalConfig(const _PyCoreConfig *config);
-
 
 PyAPI_FUNC(_PyInitError) _PyMainInterpreterConfig_Read(
     _PyMainInterpreterConfig *config,
@@ -165,12 +125,6 @@
 PyAPI_FUNC(int) PyByteArray_Init(void);
 PyAPI_FUNC(_PyInitError) _Py_HashRandomization_Init(const _PyCoreConfig *);
 #endif
-#ifdef Py_BUILD_CORE
-PyAPI_FUNC(int) _Py_ReadHashSeed(
-    const char *seed_text,
-    int *use_hash_seed,
-    unsigned long *hash_seed);
-#endif
 
 /* Various internal finalizers */
 
diff --git a/Include/pystate.h b/Include/pystate.h
index b900843..bbeea9d 100644
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -8,6 +8,7 @@
 #endif
 
 #include "pythread.h"
+#include "coreconfig.h"
 
 /* This limitation is for performance and simplicity. If needed it can be
 removed (with effort). */
@@ -24,261 +25,6 @@
 #else
 typedef PyObject* (*_PyFrameEvalFunction)(struct _frame *, int);
 
-
-typedef struct {
-    /* Install signal handlers? Yes by default. */
-    int install_signal_handlers;
-
-    /* If greater than 0: use environment variables.
-       Set to 0 by -E command line option. If set to -1 (default), it is
-       set to !Py_IgnoreEnvironmentFlag. */
-    int use_environment;
-
-    int use_hash_seed;      /* PYTHONHASHSEED=x */
-    unsigned long hash_seed;
-
-    const char *allocator;  /* Memory allocator: PYTHONMALLOC */
-    int dev_mode;           /* PYTHONDEVMODE, -X dev */
-
-    /* Enable faulthandler?
-       Set to 1 by -X faulthandler and PYTHONFAULTHANDLER. -1 means unset. */
-    int faulthandler;
-
-    /* Enable tracemalloc?
-       Set by -X tracemalloc=N and PYTHONTRACEMALLOC. -1 means unset */
-    int tracemalloc;
-
-    int import_time;        /* PYTHONPROFILEIMPORTTIME, -X importtime */
-    int show_ref_count;     /* -X showrefcount */
-    int show_alloc_count;   /* -X showalloccount */
-    int dump_refs;          /* PYTHONDUMPREFS */
-    int malloc_stats;       /* PYTHONMALLOCSTATS */
-    int coerce_c_locale;    /* PYTHONCOERCECLOCALE, -1 means unknown */
-    int coerce_c_locale_warn; /* PYTHONCOERCECLOCALE=warn */
-
-    /* Enable UTF-8 mode?
-       Set by -X utf8 command line option and PYTHONUTF8 environment variable.
-       If set to -1 (default), inherit Py_UTF8Mode value. */
-    int utf8_mode;
-
-    wchar_t *pycache_prefix; /* PYTHONPYCACHEPREFIX, -X pycache_prefix=PATH */
-
-    wchar_t *program_name;  /* Program name, see also Py_GetProgramName() */
-    int argc;               /* Number of command line arguments,
-                               -1 means unset */
-    wchar_t **argv;         /* Command line arguments */
-    wchar_t *program;       /* argv[0] or "" */
-
-    int nxoption;           /* Number of -X options */
-    wchar_t **xoptions;     /* -X options */
-
-    int nwarnoption;        /* Number of warnings options */
-    wchar_t **warnoptions;  /* Warnings options */
-
-    /* Path configuration inputs */
-    wchar_t *module_search_path_env; /* PYTHONPATH environment variable */
-    wchar_t *home;          /* PYTHONHOME environment variable,
-                               see also Py_SetPythonHome(). */
-
-    /* Path configuration outputs */
-    int nmodule_search_path;        /* Number of sys.path paths,
-                                       -1 means unset */
-    wchar_t **module_search_paths;  /* sys.path paths */
-    wchar_t *executable;    /* sys.executable */
-    wchar_t *prefix;        /* sys.prefix */
-    wchar_t *base_prefix;   /* sys.base_prefix */
-    wchar_t *exec_prefix;   /* sys.exec_prefix */
-    wchar_t *base_exec_prefix;  /* sys.base_exec_prefix */
-#ifdef MS_WINDOWS
-    wchar_t *dll_path;      /* Windows DLL path */
-#endif
-
-    /* If greater than 0, enable isolated mode: sys.path contains
-       neither the script's directory nor the user's site-packages directory.
-
-       Set to 1 by the -I command line option. If set to -1 (default), inherit
-       Py_IsolatedFlag value. */
-    int isolated;
-
-    /* If equal to zero, disable the import of the module site and the
-       site-dependent manipulations of sys.path that it entails. Also disable
-       these manipulations if site is explicitly imported later (call
-       site.main() if you want them to be triggered).
-
-       Set to 0 by the -S command line option. If set to -1 (default), it is
-       set to !Py_NoSiteFlag. */
-    int site_import;
-
-    /* Bytes warnings:
-
-       * If equal to 1, issue a warning when comparing bytes or bytearray with
-         str or bytes with int.
-       * If equal or greater to 2, issue an error.
-
-       Incremented by the -b command line option. If set to -1 (default), inherit
-       Py_BytesWarningFlag value. */
-    int bytes_warning;
-
-    /* If greater than 0, enable inspect: when a script is passed as first
-       argument or the -c option is used, enter interactive mode after
-       executing the script or the command, even when sys.stdin does not appear
-       to be a terminal.
-
-       Incremented by the -i command line option. Set to 1 if the PYTHONINSPECT
-       environment variable is non-empty. If set to -1 (default), inherit
-       Py_InspectFlag value. */
-    int inspect;
-
-    /* If greater than 0: enable the interactive mode (REPL).
-
-       Incremented by the -i command line option. If set to -1 (default),
-       inherit Py_InteractiveFlag value. */
-    int interactive;
-
-    /* Optimization level.
-
-       Incremented by the -O command line option. Set by the PYTHONOPTIMIZE
-       environment variable. If set to -1 (default), inherit Py_OptimizeFlag
-       value. */
-    int optimization_level;
-
-    /* If greater than 0, enable the debug mode: turn on parser debugging
-       output (for expert only, depending on compilation options).
-
-       Incremented by the -d command line option. Set by the PYTHONDEBUG
-       environment variable. If set to -1 (default), inherit Py_DebugFlag
-       value. */
-    int parser_debug;
-
-    /* If equal to 0, Python won't try to write ``.pyc`` files on the
-       import of source modules.
-
-       Set to 0 by the -B command line option and the PYTHONDONTWRITEBYTECODE
-       environment variable. If set to -1 (default), it is set to
-       !Py_DontWriteBytecodeFlag. */
-    int write_bytecode;
-
-    /* If greater than 0, enable the verbose mode: print a message each time a
-       module is initialized, showing the place (filename or built-in module)
-       from which it is loaded.
-
-       If greater or equal to 2, print a message for each file that is checked
-       for when searching for a module. Also provides information on module
-       cleanup at exit.
-
-       Incremented by the -v option. Set by the PYTHONVERBOSE environment
-       variable. If set to -1 (default), inherit Py_VerboseFlag value. */
-    int verbose;
-
-    /* If greater than 0, enable the quiet mode: Don't display the copyright
-       and version messages even in interactive mode.
-
-       Incremented by the -q option. If set to -1 (default), inherit
-       Py_QuietFlag value. */
-    int quiet;
-
-   /* If greater than 0, don't add the user site-packages directory to
-      sys.path.
-
-      Set to 0 by the -s and -I command line options , and the PYTHONNOUSERSITE
-      environment variable. If set to -1 (default), it is set to
-      !Py_NoUserSiteDirectory. */
-    int user_site_directory;
-
-    /* If equal to 0, enable unbuffered mode: force the stdout and stderr
-       streams to be unbuffered.
-
-       Set to 0 by the -u option. Set by the PYTHONUNBUFFERED environment
-       variable.
-       If set to -1 (default), it is set to !Py_UnbufferedStdioFlag. */
-    int buffered_stdio;
-
-#ifdef MS_WINDOWS
-    /* If greater than 1, use the "mbcs" encoding instead of the UTF-8
-       encoding for the filesystem encoding.
-
-       Set to 1 if the PYTHONLEGACYWINDOWSFSENCODING environment variable is
-       set to a non-empty string. If set to -1 (default), inherit
-       Py_LegacyWindowsFSEncodingFlag value.
-
-       See PEP 529 for more details. */
-    int legacy_windows_fs_encoding;
-
-    /* If greater than zero, use io.FileIO instead of WindowsConsoleIO for sys
-       standard streams.
-
-       Set to 1 if the PYTHONLEGACYWINDOWSSTDIO environment variable is set to
-       a non-empty string. If set to -1 (default), inherit
-       Py_LegacyWindowsStdioFlag value.
-
-       See PEP 528 for more details. */
-    int legacy_windows_stdio;
-#endif
-
-    /* --- Private fields -------- */
-
-    /* Install importlib? If set to 0, importlib is not initialized at all.
-       Needed by freeze_importlib. */
-    int _install_importlib;
-
-    /* Value of the --check-hash-based-pycs configure option. Valid values:
-
-       - "default" means the 'check_source' flag in hash-based pycs
-         determines invalidation
-       - "always" causes the interpreter to hash the source file for
-         invalidation regardless of value of 'check_source' bit
-       - "never" causes the interpreter to always assume hash-based pycs are
-         valid
-
-       Set by the --check-hash-based-pycs command line option.
-       If set to NULL (default), inherit _Py_CheckHashBasedPycsMode value.
-
-       See PEP 552 "Deterministic pycs" for more details. */
-    const char *_check_hash_pycs_mode;
-
-    /* If greater than 0, suppress _PyPathConfig_Calculate() warnings.
-
-       If set to -1 (default), inherit Py_FrozenFlag value. */
-    int _frozen;
-
-} _PyCoreConfig;
-
-#ifdef MS_WINDOWS
-#  define _PyCoreConfig_WINDOWS_INIT \
-        .legacy_windows_fs_encoding = -1, \
-        .legacy_windows_stdio = -1,
-#else
-#  define _PyCoreConfig_WINDOWS_INIT
-#endif
-
-#define _PyCoreConfig_INIT \
-    (_PyCoreConfig){ \
-        .install_signal_handlers = 1, \
-        .use_environment = -1, \
-        .use_hash_seed = -1, \
-        .faulthandler = -1, \
-        .tracemalloc = -1, \
-        .coerce_c_locale = -1, \
-        .utf8_mode = -1, \
-        .argc = -1, \
-        .nmodule_search_path = -1, \
-        .isolated = -1, \
-        .site_import = -1, \
-        .bytes_warning = -1, \
-        .inspect = -1, \
-        .interactive = -1, \
-        .optimization_level = -1, \
-        .parser_debug= -1, \
-        .write_bytecode = -1, \
-        .verbose = -1, \
-        .quiet = -1, \
-        .user_site_directory = -1, \
-        .buffered_stdio = -1, \
-        _PyCoreConfig_WINDOWS_INIT \
-        ._install_importlib = 1, \
-        ._frozen = -1}
-/* Note: _PyCoreConfig_INIT sets other fields to 0/NULL */
-
 /* Placeholders while working on the new configuration API
  *
  * See PEP 432 for final anticipated contents
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 51cf2fd..d60d48e 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -329,8 +329,9 @@
 		Python/ast_unparse.o \
 		Python/bltinmodule.o \
 		Python/ceval.o \
-		Python/compile.o \
 		Python/codecs.o \
+		Python/compile.o \
+		Python/coreconfig.o \
 		Python/dynamic_annotations.o \
 		Python/errors.o \
 		Python/frozenmain.o \
@@ -944,6 +945,7 @@
 		$(srcdir)/Include/codecs.h \
 		$(srcdir)/Include/compile.h \
 		$(srcdir)/Include/complexobject.h \
+		$(srcdir)/Include/coreconfig.h \
 		$(srcdir)/Include/descrobject.h \
 		$(srcdir)/Include/dictobject.h \
 		$(srcdir)/Include/dtoa.h \
diff --git a/Modules/main.c b/Modules/main.c
index 34069e1..f99ff86 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -2,7 +2,6 @@
 
 #include "Python.h"
 #include "osdefs.h"
-#include "internal/import.h"
 #include "internal/pygetopt.h"
 #include "internal/pystate.h"
 
@@ -46,16 +45,6 @@
      : _Py_INIT_NO_MEMORY())
 
 
-#define SET_DECODE_ERROR(NAME, LEN) \
-    do { \
-        if ((LEN) == (size_t)-2) { \
-            pymain->err = _Py_INIT_USER_ERR("cannot decode " NAME); \
-        } \
-        else { \
-            pymain->err = _Py_INIT_NO_MEMORY(); \
-        } \
-    } while (0)
-
 #ifdef MS_WINDOWS
 #define WCSTOK wcstok_s
 #else
@@ -168,71 +157,6 @@
 }
 
 
-static const char*
-config_get_env_var(const _PyCoreConfig *config, const char *name)
-{
-    assert(config->use_environment >= 0);
-
-    if (!config->use_environment) {
-        return NULL;
-    }
-
-    const char *var = getenv(name);
-    if (var && var[0] != '\0') {
-        return var;
-    }
-    else {
-        return NULL;
-    }
-}
-
-
-static int
-config_get_env_var_dup(const _PyCoreConfig *config, wchar_t **dest, wchar_t *wname, char *name)
-{
-    assert(config->use_environment >= 0);
-
-    if (!config->use_environment) {
-        *dest = NULL;
-        return 0;
-    }
-
-#ifdef MS_WINDOWS
-    const wchar_t *var = _wgetenv(wname);
-    if (!var || var[0] == '\0') {
-        *dest = NULL;
-        return 0;
-    }
-
-    wchar_t *copy = _PyMem_RawWcsdup(var);
-    if (copy == NULL) {
-        return -1;
-    }
-
-    *dest = copy;
-#else
-    const char *var = getenv(name);
-    if (!var || var[0] == '\0') {
-        *dest = NULL;
-        return 0;
-    }
-
-    size_t len;
-    wchar_t *wvar = Py_DecodeLocale(var, &len);
-    if (!wvar) {
-        if (len == (size_t)-2) {
-            return -2;
-        }
-        else {
-            return -1;
-        }
-    }
-    *dest = wvar;
-#endif
-    return 0;
-}
-
-
 static void
 pymain_run_interactive_hook(void)
 {
@@ -457,34 +381,6 @@
      || pymain->module != NULL)
 
 
-static void
-clear_wstrlist(int len, wchar_t **list)
-{
-    for (int i=0; i < len; i++) {
-        PyMem_RawFree(list[i]);
-    }
-    PyMem_RawFree(list);
-}
-
-
-static wchar_t**
-copy_wstrlist(int len, wchar_t **list)
-{
-    assert((len > 0 && list != NULL) || len == 0);
-    size_t size = len * sizeof(list[0]);
-    wchar_t **list_copy = PyMem_RawMalloc(size);
-    for (int i=0; i < len; i++) {
-        wchar_t* arg = _PyMem_RawWcsdup(list[i]);
-        if (arg == NULL) {
-            clear_wstrlist(i, list);
-            return NULL;
-        }
-        list_copy[i] = arg;
-    }
-    return list_copy;
-}
-
-
 static wchar_t*
 pymain_wstrdup(_PyMain *pymain, const wchar_t *str)
 {
@@ -516,7 +412,7 @@
             size_t len;
             wchar_t *arg = Py_DecodeLocale(pymain->bytes_argv[i], &len);
             if (arg == NULL) {
-                clear_wstrlist(i, argv);
+                _Py_wstrlist_clear(i, argv);
                 pymain->err = DECODE_LOCALE_ERR("command line arguments",
                                                 (Py_ssize_t)len);
                 return -1;
@@ -548,243 +444,21 @@
 
 
 static void
-_PyCoreConfig_GetGlobalConfig(_PyCoreConfig *config)
-{
-#define COPY_FLAG(ATTR, VALUE) \
-        if (config->ATTR == -1) { \
-            config->ATTR = VALUE; \
-        }
-#define COPY_NOT_FLAG(ATTR, VALUE) \
-        if (config->ATTR == -1) { \
-            config->ATTR = !(VALUE); \
-        }
-
-    COPY_FLAG(utf8_mode, Py_UTF8Mode);
-    COPY_FLAG(isolated, Py_IsolatedFlag);
-    COPY_FLAG(bytes_warning, Py_BytesWarningFlag);
-    COPY_FLAG(inspect, Py_InspectFlag);
-    COPY_FLAG(interactive, Py_InteractiveFlag);
-    COPY_FLAG(optimization_level, Py_OptimizeFlag);
-    COPY_FLAG(parser_debug, Py_DebugFlag);
-    COPY_FLAG(verbose, Py_VerboseFlag);
-    COPY_FLAG(quiet, Py_QuietFlag);
-#ifdef MS_WINDOWS
-    COPY_FLAG(legacy_windows_fs_encoding, Py_LegacyWindowsFSEncodingFlag);
-    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
-#endif
-    COPY_FLAG(_frozen, Py_FrozenFlag);
-
-    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
-    COPY_NOT_FLAG(buffered_stdio, Py_UnbufferedStdioFlag);
-    COPY_NOT_FLAG(site_import, Py_NoSiteFlag);
-    COPY_NOT_FLAG(write_bytecode, Py_DontWriteBytecodeFlag);
-    COPY_NOT_FLAG(user_site_directory, Py_NoUserSiteDirectory);
-
-    if (config->_check_hash_pycs_mode == NULL) {
-        config->_check_hash_pycs_mode = _Py_CheckHashBasedPycsMode;
-    }
-
-#undef COPY_FLAG
-#undef COPY_NOT_FLAG
-}
-
-
-/* Set Py_xxx global configuration variables from 'config' configuration. */
-void
-_PyCoreConfig_SetGlobalConfig(const _PyCoreConfig *config)
-{
-#define COPY_FLAG(ATTR, VAR) \
-        if (config->ATTR != -1) { \
-            VAR = config->ATTR; \
-        }
-#define COPY_NOT_FLAG(ATTR, VAR) \
-        if (config->ATTR != -1) { \
-            VAR = !config->ATTR; \
-        }
-
-    COPY_FLAG(utf8_mode, Py_UTF8Mode);
-    COPY_FLAG(isolated, Py_IsolatedFlag);
-    COPY_FLAG(bytes_warning, Py_BytesWarningFlag);
-    COPY_FLAG(inspect, Py_InspectFlag);
-    COPY_FLAG(interactive, Py_InteractiveFlag);
-    COPY_FLAG(optimization_level, Py_OptimizeFlag);
-    COPY_FLAG(parser_debug, Py_DebugFlag);
-    COPY_FLAG(verbose, Py_VerboseFlag);
-    COPY_FLAG(quiet, Py_QuietFlag);
-#ifdef MS_WINDOWS
-    COPY_FLAG(legacy_windows_fs_encoding, Py_LegacyWindowsFSEncodingFlag);
-    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
-#endif
-
-    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
-    COPY_NOT_FLAG(buffered_stdio, Py_UnbufferedStdioFlag);
-    COPY_NOT_FLAG(site_import, Py_NoSiteFlag);
-    COPY_NOT_FLAG(write_bytecode, Py_DontWriteBytecodeFlag);
-    COPY_NOT_FLAG(user_site_directory, Py_NoUserSiteDirectory);
-
-    if (config->_check_hash_pycs_mode != NULL) {
-        _Py_CheckHashBasedPycsMode = config->_check_hash_pycs_mode;
-    }
-
-    /* Random or non-zero hash seed */
-    Py_HashRandomizationFlag = (config->use_hash_seed == 0 ||
-                                config->hash_seed != 0);
-
-#undef COPY_FLAG
-#undef COPY_NOT_FLAG
-}
-
-
-/* Free memory allocated in config, but don't clear all attributes */
-void
-_PyCoreConfig_Clear(_PyCoreConfig *config)
-{
-#define CLEAR(ATTR) \
-    do { \
-        PyMem_RawFree(ATTR); \
-        ATTR = NULL; \
-    } while (0)
-#define CLEAR_WSTRLIST(LEN, LIST) \
-    do { \
-        clear_wstrlist(LEN, LIST); \
-        LEN = 0; \
-        LIST = NULL; \
-    } while (0)
-
-    CLEAR(config->pycache_prefix);
-    CLEAR(config->module_search_path_env);
-    CLEAR(config->home);
-    CLEAR(config->program_name);
-    CLEAR(config->program);
-
-    CLEAR_WSTRLIST(config->argc, config->argv);
-    config->argc = -1;
-
-    CLEAR_WSTRLIST(config->nwarnoption, config->warnoptions);
-    CLEAR_WSTRLIST(config->nxoption, config->xoptions);
-    CLEAR_WSTRLIST(config->nmodule_search_path, config->module_search_paths);
-    config->nmodule_search_path = -1;
-
-    CLEAR(config->executable);
-    CLEAR(config->prefix);
-    CLEAR(config->base_prefix);
-    CLEAR(config->exec_prefix);
-#ifdef MS_WINDOWS
-    CLEAR(config->dll_path);
-#endif
-    CLEAR(config->base_exec_prefix);
-#undef CLEAR
-#undef CLEAR_WSTRLIST
-}
-
-
-int
-_PyCoreConfig_Copy(_PyCoreConfig *config, const _PyCoreConfig *config2)
-{
-    _PyCoreConfig_Clear(config);
-
-#define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
-#define COPY_STR_ATTR(ATTR) \
-    do { \
-        if (config2->ATTR != NULL) { \
-            config->ATTR = _PyMem_RawWcsdup(config2->ATTR); \
-            if (config->ATTR == NULL) { \
-                return -1; \
-            } \
-        } \
-    } while (0)
-#define COPY_WSTRLIST(LEN, LIST) \
-    do { \
-        if (config2->LIST != NULL) { \
-            config->LIST = copy_wstrlist(config2->LEN, config2->LIST); \
-            if (config->LIST == NULL) { \
-                return -1; \
-            } \
-        } \
-        config->LEN = config2->LEN; \
-    } while (0)
-
-    COPY_ATTR(install_signal_handlers);
-    COPY_ATTR(use_environment);
-    COPY_ATTR(use_hash_seed);
-    COPY_ATTR(hash_seed);
-    COPY_ATTR(_install_importlib);
-    COPY_ATTR(allocator);
-    COPY_ATTR(dev_mode);
-    COPY_ATTR(faulthandler);
-    COPY_ATTR(tracemalloc);
-    COPY_ATTR(import_time);
-    COPY_ATTR(show_ref_count);
-    COPY_ATTR(show_alloc_count);
-    COPY_ATTR(dump_refs);
-    COPY_ATTR(malloc_stats);
-
-    COPY_ATTR(coerce_c_locale);
-    COPY_ATTR(coerce_c_locale_warn);
-    COPY_ATTR(utf8_mode);
-
-    COPY_STR_ATTR(pycache_prefix);
-    COPY_STR_ATTR(module_search_path_env);
-    COPY_STR_ATTR(home);
-    COPY_STR_ATTR(program_name);
-    COPY_STR_ATTR(program);
-
-    COPY_WSTRLIST(argc, argv);
-    COPY_WSTRLIST(nwarnoption, warnoptions);
-    COPY_WSTRLIST(nxoption, xoptions);
-    COPY_WSTRLIST(nmodule_search_path, module_search_paths);
-
-    COPY_STR_ATTR(executable);
-    COPY_STR_ATTR(prefix);
-    COPY_STR_ATTR(base_prefix);
-    COPY_STR_ATTR(exec_prefix);
-#ifdef MS_WINDOWS
-    COPY_STR_ATTR(dll_path);
-#endif
-    COPY_STR_ATTR(base_exec_prefix);
-
-    COPY_ATTR(isolated);
-    COPY_ATTR(site_import);
-    COPY_ATTR(bytes_warning);
-    COPY_ATTR(inspect);
-    COPY_ATTR(interactive);
-    COPY_ATTR(optimization_level);
-    COPY_ATTR(parser_debug);
-    COPY_ATTR(write_bytecode);
-    COPY_ATTR(verbose);
-    COPY_ATTR(quiet);
-    COPY_ATTR(user_site_directory);
-    COPY_ATTR(buffered_stdio);
-#ifdef MS_WINDOWS
-    COPY_ATTR(legacy_windows_fs_encoding);
-    COPY_ATTR(legacy_windows_stdio);
-#endif
-    COPY_ATTR(_check_hash_pycs_mode);
-    COPY_ATTR(_frozen);
-
-#undef COPY_ATTR
-#undef COPY_STR_ATTR
-#undef COPY_WSTRLIST
-    return 0;
-}
-
-
-static void
 pymain_clear_cmdline(_PyMain *pymain, _PyCmdline *cmdline)
 {
     PyMemAllocatorEx old_alloc;
     _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
 
-    clear_wstrlist(cmdline->nwarnoption, cmdline->warnoptions);
+    _Py_wstrlist_clear(cmdline->nwarnoption, cmdline->warnoptions);
     cmdline->nwarnoption = 0;
     cmdline->warnoptions = NULL;
 
-    clear_wstrlist(cmdline->nenv_warnoption, cmdline->env_warnoptions);
+    _Py_wstrlist_clear(cmdline->nenv_warnoption, cmdline->env_warnoptions);
     cmdline->nenv_warnoption = 0;
     cmdline->env_warnoptions = NULL;
 
     if (pymain->use_bytes_argv && cmdline->argv != NULL) {
-        clear_wstrlist(pymain->argc, cmdline->argv);
+        _Py_wstrlist_clear(pymain->argc, cmdline->argv);
     }
     cmdline->argv = NULL;
 
@@ -838,7 +512,7 @@
 
     pymain_clear_pymain(pymain);
 
-    clear_wstrlist(orig_argc, orig_argv);
+    _Py_wstrlist_clear(orig_argc, orig_argv);
     orig_argc = 0;
     orig_argv = NULL;
 
@@ -1245,8 +919,8 @@
                              _PyCmdline *cmdline)
 {
     wchar_t *env;
-    int res = config_get_env_var_dup(config, &env,
-                                     L"PYTHONWARNINGS", "PYTHONWARNINGS");
+    int res = _PyCoreConfig_GetEnvDup(config, &env,
+                                      L"PYTHONWARNINGS", "PYTHONWARNINGS");
     if (res < 0) {
         return DECODE_LOCALE_ERR("PYTHONWARNINGS", res);
     }
@@ -1314,85 +988,6 @@
 }
 
 
-/* Get the program name: use PYTHONEXECUTABLE and __PYVENV_LAUNCHER__
-   environment variables on macOS if available. */
-static _PyInitError
-config_init_program_name(_PyCoreConfig *config)
-{
-    /* If Py_SetProgramName() was called, use its value */
-    const wchar_t *program_name = _Py_path_config.program_name;
-    if (program_name != NULL) {
-        config->program_name = _PyMem_RawWcsdup(program_name);
-        if (config->program_name == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-        return _Py_INIT_OK();
-    }
-
-#ifdef __APPLE__
-    /* On MacOS X, when the Python interpreter is embedded in an
-       application bundle, it gets executed by a bootstrapping script
-       that does os.execve() with an argv[0] that's different from the
-       actual Python executable. This is needed to keep the Finder happy,
-       or rather, to work around Apple's overly strict requirements of
-       the process name. However, we still need a usable sys.executable,
-       so the actual executable path is passed in an environment variable.
-       See Lib/plat-mac/bundlebuiler.py for details about the bootstrap
-       script. */
-    const char *p = config_get_env_var(config, "PYTHONEXECUTABLE");
-    if (p != NULL) {
-        size_t len;
-        wchar_t* program_name = Py_DecodeLocale(p, &len);
-        if (program_name == NULL) {
-            return DECODE_LOCALE_ERR("PYTHONEXECUTABLE environment "
-                                     "variable", (Py_ssize_t)len);
-        }
-        config->program_name = program_name;
-        return _Py_INIT_OK();
-    }
-#ifdef WITH_NEXT_FRAMEWORK
-    else {
-        const char* pyvenv_launcher = getenv("__PYVENV_LAUNCHER__");
-        if (pyvenv_launcher && *pyvenv_launcher) {
-            /* Used by Mac/Tools/pythonw.c to forward
-             * the argv0 of the stub executable
-             */
-            size_t len;
-            wchar_t* program_name = Py_DecodeLocale(pyvenv_launcher, &len);
-            if (program_name == NULL) {
-                return DECODE_LOCALE_ERR("__PYVENV_LAUNCHER__ environment "
-                                         "variable", (Py_ssize_t)len);
-            }
-            config->program_name = program_name;
-            return _Py_INIT_OK();
-        }
-    }
-#endif   /* WITH_NEXT_FRAMEWORK */
-#endif   /* __APPLE__ */
-
-    /* Use argv[0] by default, if available */
-    if (config->program != NULL) {
-        config->program_name = _PyMem_RawWcsdup(config->program);
-        if (config->program_name == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-        return _Py_INIT_OK();
-    }
-
-    /* Last fall back: hardcoded string */
-#ifdef MS_WINDOWS
-    const wchar_t *default_program_name = L"python";
-#else
-    const wchar_t *default_program_name = L"python3";
-#endif
-    config->program_name = _PyMem_RawWcsdup(default_program_name);
-    if (config->program_name == NULL) {
-        return _Py_INIT_NO_MEMORY();
-    }
-    return _Py_INIT_OK();
-}
-
-
 static void
 pymain_header(_PyMain *pymain)
 {
@@ -1422,10 +1017,10 @@
         /* Ensure at least one (empty) argument is seen */
         static wchar_t *empty_argv[1] = {L""};
         argc = 1;
-        argv = copy_wstrlist(1, empty_argv);
+        argv = _Py_wstrlist_copy(1, empty_argv);
     }
     else {
-        argv = copy_wstrlist(argc, &cmdline->argv[_PyOS_optind]);
+        argv = _Py_wstrlist_copy(argc, &cmdline->argv[_PyOS_optind]);
     }
 
     if (argv == NULL) {
@@ -1445,7 +1040,7 @@
     if (arg0 != NULL) {
         arg0 = _PyMem_RawWcsdup(arg0);
         if (arg0 == NULL) {
-            clear_wstrlist(argc, argv);
+            _Py_wstrlist_clear(argc, argv);
             pymain->err = _Py_INIT_NO_MEMORY();
             return -1;
         }
@@ -1558,7 +1153,7 @@
 static void
 pymain_run_startup(_PyMain *pymain, _PyCoreConfig *config, PyCompilerFlags *cf)
 {
-    const char *startup = config_get_env_var(config, "PYTHONSTARTUP");
+    const char *startup = _PyCoreConfig_GetEnv(config, "PYTHONSTARTUP");
     if (startup == NULL) {
         return;
     }
@@ -1613,7 +1208,7 @@
 {
     /* Check this environment variable at the end, to give programs the
        opportunity to set it from Python. */
-    if (!Py_InspectFlag && config_get_env_var(config, "PYTHONINSPECT")) {
+    if (!Py_InspectFlag && _PyCoreConfig_GetEnv(config, "PYTHONINSPECT")) {
         Py_InspectFlag = 1;
         config->inspect = 1;
     }
@@ -1660,359 +1255,6 @@
 }
 
 
-static const wchar_t*
-config_get_xoption(_PyCoreConfig *config, wchar_t *name)
-{
-    int nxoption = config->nxoption;
-    wchar_t **xoptions = config->xoptions;
-    for (int i=0; i < nxoption; i++) {
-        wchar_t *option = xoptions[i];
-        size_t len;
-        wchar_t *sep = wcschr(option, L'=');
-        if (sep != NULL) {
-            len = (sep - option);
-        }
-        else {
-            len = wcslen(option);
-        }
-        if (wcsncmp(option, name, len) == 0 && name[len] == L'\0') {
-            return option;
-        }
-    }
-    return NULL;
-}
-
-
-static int
-pymain_str_to_int(const char *str, int *result)
-{
-    errno = 0;
-    const char *endptr = str;
-    long value = strtol(str, (char **)&endptr, 10);
-    if (*endptr != '\0' || errno == ERANGE) {
-        return -1;
-    }
-    if (value < INT_MIN || value > INT_MAX) {
-        return -1;
-    }
-
-    *result = (int)value;
-    return 0;
-}
-
-
-static int
-pymain_wstr_to_int(const wchar_t *wstr, int *result)
-{
-    errno = 0;
-    const wchar_t *endptr = wstr;
-    long value = wcstol(wstr, (wchar_t **)&endptr, 10);
-    if (*endptr != '\0' || errno == ERANGE) {
-        return -1;
-    }
-    if (value < INT_MIN || value > INT_MAX) {
-        return -1;
-    }
-
-    *result = (int)value;
-    return 0;
-}
-
-
-static _PyInitError
-pymain_init_tracemalloc(_PyCoreConfig *config)
-{
-    int nframe;
-    int valid;
-
-    const char *env = config_get_env_var(config, "PYTHONTRACEMALLOC");
-    if (env) {
-        if (!pymain_str_to_int(env, &nframe)) {
-            valid = (nframe >= 0);
-        }
-        else {
-            valid = 0;
-        }
-        if (!valid) {
-            return _Py_INIT_USER_ERR("PYTHONTRACEMALLOC: invalid number "
-                                     "of frames");
-        }
-        config->tracemalloc = nframe;
-    }
-
-    const wchar_t *xoption = config_get_xoption(config, L"tracemalloc");
-    if (xoption) {
-        const wchar_t *sep = wcschr(xoption, L'=');
-        if (sep) {
-            if (!pymain_wstr_to_int(sep + 1, &nframe)) {
-                valid = (nframe >= 0);
-            }
-            else {
-                valid = 0;
-            }
-            if (!valid) {
-                return _Py_INIT_USER_ERR("-X tracemalloc=NFRAME: "
-                                         "invalid number of frames");
-            }
-        }
-        else {
-            /* -X tracemalloc behaves as -X tracemalloc=1 */
-            nframe = 1;
-        }
-        config->tracemalloc = nframe;
-    }
-    return _Py_INIT_OK();
-}
-
-
-static _PyInitError
-pymain_init_pycache_prefix(_PyCoreConfig *config)
-{
-    const wchar_t *xoption = config_get_xoption(config, L"pycache_prefix");
-    if (xoption) {
-        const wchar_t *sep = wcschr(xoption, L'=');
-        if (sep && wcslen(sep) > 1) {
-            config->pycache_prefix = _PyMem_RawWcsdup(sep + 1);
-            if (config->pycache_prefix == NULL) {
-                return _Py_INIT_NO_MEMORY();
-            }
-        } else {
-            // -X pycache_prefix= can cancel the env var
-            config->pycache_prefix = NULL;
-        }
-        return _Py_INIT_OK();
-    }
-
-    wchar_t *env;
-    int res = config_get_env_var_dup(config, &env,
-                                     L"PYTHONPYCACHEPREFIX", "PYTHONPYCACHEPREFIX");
-    if (res < 0) {
-        return DECODE_LOCALE_ERR("PYTHONPYCACHEPREFIX", res);
-    } else if (env) {
-        config->pycache_prefix = env;
-    }
-
-    return _Py_INIT_OK();
-}
-
-
-static void
-get_env_flag(_PyCoreConfig *config, int *flag, const char *name)
-{
-    const char *var = config_get_env_var(config, name);
-    if (!var) {
-        return;
-    }
-    int value;
-    if (pymain_str_to_int(var, &value) < 0 || value < 0) {
-        /* PYTHONDEBUG=text and PYTHONDEBUG=-2 behave as PYTHONDEBUG=1 */
-        value = 1;
-    }
-    if (*flag < value) {
-        *flag = value;
-    }
-}
-
-
-static _PyInitError
-config_init_home(_PyCoreConfig *config)
-{
-    wchar_t *home;
-
-    /* If Py_SetPythonHome() was called, use its value */
-    home = _Py_path_config.home;
-    if (home) {
-        config->home = _PyMem_RawWcsdup(home);
-        if (config->home == NULL) {
-            return _Py_INIT_NO_MEMORY();
-        }
-        return _Py_INIT_OK();
-    }
-
-    int res = config_get_env_var_dup(config, &home, L"PYTHONHOME", "PYTHONHOME");
-    if (res < 0) {
-        return DECODE_LOCALE_ERR("PYTHONHOME", res);
-    }
-    config->home = home;
-    return _Py_INIT_OK();
-}
-
-
-static _PyInitError
-config_init_hash_seed(_PyCoreConfig *config)
-{
-    if (config->use_hash_seed < 0) {
-        const char *seed_text = config_get_env_var(config, "PYTHONHASHSEED");
-        int use_hash_seed;
-        unsigned long hash_seed;
-        if (_Py_ReadHashSeed(seed_text, &use_hash_seed, &hash_seed) < 0) {
-            return _Py_INIT_USER_ERR("PYTHONHASHSEED must be \"random\" "
-                                     "or an integer in range [0; 4294967295]");
-        }
-        config->use_hash_seed = use_hash_seed;
-        config->hash_seed = hash_seed;
-    }
-    return _Py_INIT_OK();
-}
-
-
-static _PyInitError
-config_init_utf8_mode(_PyCoreConfig *config)
-{
-    const wchar_t *xopt = config_get_xoption(config, L"utf8");
-    if (xopt) {
-        wchar_t *sep = wcschr(xopt, L'=');
-        if (sep) {
-            xopt = sep + 1;
-            if (wcscmp(xopt, L"1") == 0) {
-                config->utf8_mode = 1;
-            }
-            else if (wcscmp(xopt, L"0") == 0) {
-                config->utf8_mode = 0;
-            }
-            else {
-                return _Py_INIT_USER_ERR("invalid -X utf8 option value");
-            }
-        }
-        else {
-            config->utf8_mode = 1;
-        }
-        return _Py_INIT_OK();
-    }
-
-    const char *opt = config_get_env_var(config, "PYTHONUTF8");
-    if (opt) {
-        if (strcmp(opt, "1") == 0) {
-            config->utf8_mode = 1;
-        }
-        else if (strcmp(opt, "0") == 0) {
-            config->utf8_mode = 0;
-        }
-        else {
-            return _Py_INIT_USER_ERR("invalid PYTHONUTF8 environment "
-                                     "variable value");
-        }
-        return _Py_INIT_OK();
-    }
-
-    return _Py_INIT_OK();
-}
-
-
-static _PyInitError
-config_read_env_vars(_PyCoreConfig *config)
-{
-    assert(config->use_environment > 0);
-
-    /* Get environment variables */
-    get_env_flag(config, &config->parser_debug, "PYTHONDEBUG");
-    get_env_flag(config, &config->verbose, "PYTHONVERBOSE");
-    get_env_flag(config, &config->optimization_level, "PYTHONOPTIMIZE");
-    get_env_flag(config, &config->inspect, "PYTHONINSPECT");
-
-    int dont_write_bytecode = 0;
-    get_env_flag(config, &dont_write_bytecode, "PYTHONDONTWRITEBYTECODE");
-    if (dont_write_bytecode) {
-        config->write_bytecode = 0;
-    }
-
-    int no_user_site_directory = 0;
-    get_env_flag(config, &no_user_site_directory, "PYTHONNOUSERSITE");
-    if (no_user_site_directory) {
-        config->user_site_directory = 0;
-    }
-
-    int unbuffered_stdio = 0;
-    get_env_flag(config, &unbuffered_stdio, "PYTHONUNBUFFERED");
-    if (unbuffered_stdio) {
-        config->buffered_stdio = 0;
-    }
-
-#ifdef MS_WINDOWS
-    get_env_flag(config, &config->legacy_windows_fs_encoding,
-                 "PYTHONLEGACYWINDOWSFSENCODING");
-    get_env_flag(config, &config->legacy_windows_stdio,
-                 "PYTHONLEGACYWINDOWSSTDIO");
-#endif
-
-    if (config->allocator == NULL) {
-        config->allocator = config_get_env_var(config, "PYTHONMALLOC");
-    }
-
-    if (config_get_env_var(config, "PYTHONDUMPREFS")) {
-        config->dump_refs = 1;
-    }
-    if (config_get_env_var(config, "PYTHONMALLOCSTATS")) {
-        config->malloc_stats = 1;
-    }
-
-    const char *env = config_get_env_var(config, "PYTHONCOERCECLOCALE");
-    if (env) {
-        if (strcmp(env, "0") == 0) {
-            config->coerce_c_locale = 0;
-        }
-        else if (strcmp(env, "warn") == 0) {
-            config->coerce_c_locale_warn = 1;
-        }
-        else {
-            config->coerce_c_locale = 1;
-        }
-    }
-
-    wchar_t *path;
-    int res = config_get_env_var_dup(config, &path, L"PYTHONPATH", "PYTHONPATH");
-    if (res < 0) {
-        return DECODE_LOCALE_ERR("PYTHONPATH", res);
-    }
-    config->module_search_path_env = path;
-
-    _PyInitError err = config_init_hash_seed(config);
-    if (_Py_INIT_FAILED(err)) {
-        return err;
-    }
-
-    return _Py_INIT_OK();
-}
-
-
-static _PyInitError
-config_read_complex_options(_PyCoreConfig *config)
-{
-    /* More complex options configured by env var and -X option */
-    if (config->faulthandler < 0) {
-        if (config_get_env_var(config, "PYTHONFAULTHANDLER")
-           || config_get_xoption(config, L"faulthandler")) {
-            config->faulthandler = 1;
-        }
-    }
-    if (config_get_env_var(config, "PYTHONPROFILEIMPORTTIME")
-       || config_get_xoption(config, L"importtime")) {
-        config->import_time = 1;
-    }
-    if (config_get_xoption(config, L"dev" ) ||
-        config_get_env_var(config, "PYTHONDEVMODE"))
-    {
-        config->dev_mode = 1;
-    }
-
-    _PyInitError err;
-    if (config->tracemalloc < 0) {
-        err = pymain_init_tracemalloc(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-
-    if (config->pycache_prefix == NULL) {
-        err = pymain_init_pycache_prefix(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-    return _Py_INIT_OK();
-}
-
-
 /* Parse command line options and environment variables.
    This code must not use Python runtime apart PyMem_Raw memory allocator.
 
@@ -2165,143 +1407,6 @@
 }
 
 
-static void
-config_init_locale(_PyCoreConfig *config)
-{
-    if (config->utf8_mode >= 0 && config->coerce_c_locale >= 0) {
-        return;
-    }
-
-    if (_Py_LegacyLocaleDetected()) {
-        /* POSIX locale: enable C locale coercion and UTF-8 Mode */
-        if (config->utf8_mode < 0) {
-            config->utf8_mode = 1;
-        }
-        if (config->coerce_c_locale < 0) {
-            config->coerce_c_locale = 1;
-        }
-        return;
-    }
-}
-
-
-/* Read configuration settings from standard locations
- *
- * This function doesn't make any changes to the interpreter state - it
- * merely populates any missing configuration settings. This allows an
- * embedding application to completely override a config option by
- * setting it before calling this function, or else modify the default
- * setting before passing the fully populated config to Py_EndInitialization.
- *
- * More advanced selective initialization tricks are possible by calling
- * this function multiple times with various preconfigured settings.
- */
-
-_PyInitError
-_PyCoreConfig_Read(_PyCoreConfig *config)
-{
-    _PyInitError err;
-
-    _PyCoreConfig_GetGlobalConfig(config);
-
-    if (config->isolated > 0) {
-        config->use_environment = 0;
-        config->user_site_directory = 0;
-    }
-
-#ifdef MS_WINDOWS
-    if (config->legacy_windows_fs_encoding) {
-        config->utf8_mode = 0;
-    }
-#endif
-
-    assert(config->use_environment >= 0);
-    if (config->use_environment) {
-        err = config_read_env_vars(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-
-    /* -X options */
-    if (config_get_xoption(config, L"showrefcount")) {
-        config->show_ref_count = 1;
-    }
-    if (config_get_xoption(config, L"showalloccount")) {
-        config->show_alloc_count = 1;
-    }
-
-    err = config_read_complex_options(config);
-    if (_Py_INIT_FAILED(err)) {
-        return err;
-    }
-
-    if (config->utf8_mode < 0) {
-        err = config_init_utf8_mode(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-
-    if (config->home == NULL) {
-        err = config_init_home(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-
-    if (config->program_name == NULL) {
-        err = config_init_program_name(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-
-    config_init_locale(config);
-
-    if (config->_install_importlib) {
-        err = _PyCoreConfig_InitPathConfig(config);
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
-
-    /* default values */
-    if (config->dev_mode) {
-        if (config->faulthandler < 0) {
-            config->faulthandler = 1;
-        }
-        if (config->allocator == NULL) {
-            config->allocator = "debug";
-        }
-    }
-    if (config->use_hash_seed < 0) {
-        config->use_hash_seed = 0;
-        config->hash_seed = 0;
-    }
-    if (config->faulthandler < 0) {
-        config->faulthandler = 0;
-    }
-    if (config->tracemalloc < 0) {
-        config->tracemalloc = 0;
-    }
-    if (config->coerce_c_locale < 0) {
-        config->coerce_c_locale = 0;
-    }
-    if (config->utf8_mode < 0) {
-        config->utf8_mode = 0;
-    }
-    if (config->_frozen < 0) {
-        config->_frozen = 0;
-    }
-    if (config->argc < 0) {
-        config->argc = 0;
-    }
-
-    return _Py_INIT_OK();
-}
-
-
 void
 _PyMainInterpreterConfig_Clear(_PyMainInterpreterConfig *config)
 {
@@ -2373,8 +1478,6 @@
 }
 
 
-
-
 _PyInitError
 _PyMainInterpreterConfig_Read(_PyMainInterpreterConfig *main_config,
                               const _PyCoreConfig *config)
@@ -2557,7 +1660,7 @@
     }
 
     /* For Py_GetArgcArgv(). Cleared by pymain_free(). */
-    orig_argv = copy_wstrlist(pymain->argc, cmdline->argv);
+    orig_argv = _Py_wstrlist_copy(pymain->argc, cmdline->argv);
     if (orig_argv == NULL) {
         pymain->err = _Py_INIT_NO_MEMORY();
         return -1;
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 90330fa..42455f5 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -95,6 +95,7 @@
     <ClInclude Include="..\Include\compile.h" />
     <ClInclude Include="..\Include\complexobject.h" />
     <ClInclude Include="..\Include\context.h" />
+    <ClInclude Include="..\Include\coreconfig.h" />
     <ClInclude Include="..\Include\datetime.h" />
     <ClInclude Include="..\Include\descrobject.h" />
     <ClInclude Include="..\Include\dictobject.h" />
@@ -367,6 +368,7 @@
     <ClCompile Include="..\Python\codecs.c" />
     <ClCompile Include="..\Python\compile.c" />
     <ClCompile Include="..\Python\context.c" />
+    <ClCompile Include="..\Python\coreconfig.c" />
     <ClCompile Include="..\Python\dynamic_annotations.c" />
     <ClCompile Include="..\Python\dynload_win.c" />
     <ClCompile Include="..\Python\errors.c" />
diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters
index b51fd54..582114f 100644
--- a/PCbuild/pythoncore.vcxproj.filters
+++ b/PCbuild/pythoncore.vcxproj.filters
@@ -84,6 +84,9 @@
     <ClInclude Include="..\Include\context.h">
       <Filter>Include</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\coreconfig.h">
+      <Filter>Include</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\datetime.h">
       <Filter>Include</Filter>
     </ClInclude>
@@ -857,6 +860,9 @@
     <ClCompile Include="..\Python\compile.c">
       <Filter>Python</Filter>
     </ClCompile>
+    <ClCompile Include="..\Python\coreconfig.c">
+      <Filter>Python</Filter>
+    </ClCompile>
     <ClCompile Include="..\Python\context.h">
       <Filter>Python</Filter>
     </ClCompile>
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 7bb5687..4b12048 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -11,29 +11,6 @@
 
 #include <ctype.h>
 
-/* The default encoding used by the platform file system APIs
-   Can remain NULL for all platforms that don't have such a concept
-
-   Don't forget to modify PyUnicode_DecodeFSDefault() if you touch any of the
-   values for Py_FileSystemDefaultEncoding!
-*/
-#if defined(__APPLE__)
-const char *Py_FileSystemDefaultEncoding = "utf-8";
-int Py_HasFileSystemDefaultEncoding = 1;
-#elif defined(MS_WINDOWS)
-/* may be changed by initfsencoding(), but should never be free()d */
-const char *Py_FileSystemDefaultEncoding = "utf-8";
-int Py_HasFileSystemDefaultEncoding = 1;
-#else
-const char *Py_FileSystemDefaultEncoding = NULL; /* set by initfsencoding() */
-int Py_HasFileSystemDefaultEncoding = 0;
-#endif
-const char *Py_FileSystemDefaultEncodeErrors = "surrogateescape";
-/* UTF-8 mode (PEP 540): if equals to 1, use the UTF-8 encoding, and change
-   stdin and stdout error handler to "surrogateescape". It is equal to
-   -1 by default: unknown, will be set by Py_Main() */
-int Py_UTF8Mode = -1;
-
 _Py_IDENTIFIER(__builtins__);
 _Py_IDENTIFIER(__dict__);
 _Py_IDENTIFIER(__prepare__);
diff --git a/Python/bootstrap_hash.c b/Python/bootstrap_hash.c
index 073b2ea..7b187f1 100644
--- a/Python/bootstrap_hash.c
+++ b/Python/bootstrap_hash.c
@@ -538,35 +538,6 @@
     return pyurandom(buffer, size, 0, 1);
 }
 
-int
-_Py_ReadHashSeed(const char *seed_text,
-                 int *use_hash_seed,
-                 unsigned long *hash_seed)
-{
-    Py_BUILD_ASSERT(sizeof(_Py_HashSecret_t) == sizeof(_Py_HashSecret.uc));
-    /* Convert a text seed to a numeric one */
-    if (seed_text && *seed_text != '\0' && strcmp(seed_text, "random") != 0) {
-        const char *endptr = seed_text;
-        unsigned long seed;
-        seed = strtoul(seed_text, (char **)&endptr, 10);
-        if (*endptr != '\0'
-            || seed > 4294967295UL
-            || (errno == ERANGE && seed == ULONG_MAX))
-        {
-            return -1;
-        }
-        /* Use a specific hash */
-        *use_hash_seed = 1;
-        *hash_seed = seed;
-    }
-    else {
-        /* Use a random hash */
-        *use_hash_seed = 0;
-        *hash_seed = 0;
-    }
-    return 0;
-}
-
 
 _PyInitError
 _Py_HashRandomization_Init(const _PyCoreConfig *config)
diff --git a/Python/coreconfig.c b/Python/coreconfig.c
new file mode 100644
index 0000000..7dabe5f
--- /dev/null
+++ b/Python/coreconfig.c
@@ -0,0 +1,964 @@
+#include "Python.h"
+#include "internal/import.h"
+#include "internal/pystate.h"
+
+
+#define DECODE_LOCALE_ERR(NAME, LEN) \
+    (((LEN) == -2) \
+     ? _Py_INIT_USER_ERR("cannot decode " NAME) \
+     : _Py_INIT_NO_MEMORY())
+
+
+/* Global configuration variables */
+
+/* The default encoding used by the platform file system APIs
+   Can remain NULL for all platforms that don't have such a concept
+
+   Don't forget to modify PyUnicode_DecodeFSDefault() if you touch any of the
+   values for Py_FileSystemDefaultEncoding!
+*/
+#if defined(__APPLE__)
+const char *Py_FileSystemDefaultEncoding = "utf-8";
+int Py_HasFileSystemDefaultEncoding = 1;
+#elif defined(MS_WINDOWS)
+/* may be changed by initfsencoding(), but should never be free()d */
+const char *Py_FileSystemDefaultEncoding = "utf-8";
+int Py_HasFileSystemDefaultEncoding = 1;
+#else
+const char *Py_FileSystemDefaultEncoding = NULL; /* set by initfsencoding() */
+int Py_HasFileSystemDefaultEncoding = 0;
+#endif
+const char *Py_FileSystemDefaultEncodeErrors = "surrogateescape";
+/* UTF-8 mode (PEP 540): if equals to 1, use the UTF-8 encoding, and change
+   stdin and stdout error handler to "surrogateescape". It is equal to
+   -1 by default: unknown, will be set by Py_Main() */
+int Py_UTF8Mode = -1;
+int Py_DebugFlag = 0; /* Needed by parser.c */
+int Py_VerboseFlag = 0; /* Needed by import.c */
+int Py_QuietFlag = 0; /* Needed by sysmodule.c */
+int Py_InteractiveFlag = 0; /* Needed by Py_FdIsInteractive() below */
+int Py_InspectFlag = 0; /* Needed to determine whether to exit at SystemExit */
+int Py_OptimizeFlag = 0; /* Needed by compile.c */
+int Py_NoSiteFlag = 0; /* Suppress 'import site' */
+int Py_BytesWarningFlag = 0; /* Warn on str(bytes) and str(buffer) */
+int Py_FrozenFlag = 0; /* Needed by getpath.c */
+int Py_IgnoreEnvironmentFlag = 0; /* e.g. PYTHONPATH, PYTHONHOME */
+int Py_DontWriteBytecodeFlag = 0; /* Suppress writing bytecode files (*.pyc) */
+int Py_NoUserSiteDirectory = 0; /* for -s and site.py */
+int Py_UnbufferedStdioFlag = 0; /* Unbuffered binary std{in,out,err} */
+int Py_HashRandomizationFlag = 0; /* for -R and PYTHONHASHSEED */
+int Py_IsolatedFlag = 0; /* for -I, isolate from user's env */
+#ifdef MS_WINDOWS
+int Py_LegacyWindowsFSEncodingFlag = 0; /* Uses mbcs instead of utf-8 */
+int Py_LegacyWindowsStdioFlag = 0; /* Uses FileIO instead of WindowsConsoleIO */
+#endif
+const char *_Py_CheckHashBasedPycsMode = "default";
+
+
+void
+_Py_wstrlist_clear(int len, wchar_t **list)
+{
+    for (int i=0; i < len; i++) {
+        PyMem_RawFree(list[i]);
+    }
+    PyMem_RawFree(list);
+}
+
+
+wchar_t**
+_Py_wstrlist_copy(int len, wchar_t **list)
+{
+    assert((len > 0 && list != NULL) || len == 0);
+    size_t size = len * sizeof(list[0]);
+    wchar_t **list_copy = PyMem_RawMalloc(size);
+    for (int i=0; i < len; i++) {
+        wchar_t* arg = _PyMem_RawWcsdup(list[i]);
+        if (arg == NULL) {
+            _Py_wstrlist_clear(i, list);
+            return NULL;
+        }
+        list_copy[i] = arg;
+    }
+    return list_copy;
+}
+
+
+/* Free memory allocated in config, but don't clear all attributes */
+void
+_PyCoreConfig_Clear(_PyCoreConfig *config)
+{
+#define CLEAR(ATTR) \
+    do { \
+        PyMem_RawFree(ATTR); \
+        ATTR = NULL; \
+    } while (0)
+#define CLEAR_WSTRLIST(LEN, LIST) \
+    do { \
+        _Py_wstrlist_clear(LEN, LIST); \
+        LEN = 0; \
+        LIST = NULL; \
+    } while (0)
+
+    CLEAR(config->pycache_prefix);
+    CLEAR(config->module_search_path_env);
+    CLEAR(config->home);
+    CLEAR(config->program_name);
+    CLEAR(config->program);
+
+    CLEAR_WSTRLIST(config->argc, config->argv);
+    config->argc = -1;
+
+    CLEAR_WSTRLIST(config->nwarnoption, config->warnoptions);
+    CLEAR_WSTRLIST(config->nxoption, config->xoptions);
+    CLEAR_WSTRLIST(config->nmodule_search_path, config->module_search_paths);
+    config->nmodule_search_path = -1;
+
+    CLEAR(config->executable);
+    CLEAR(config->prefix);
+    CLEAR(config->base_prefix);
+    CLEAR(config->exec_prefix);
+#ifdef MS_WINDOWS
+    CLEAR(config->dll_path);
+#endif
+    CLEAR(config->base_exec_prefix);
+#undef CLEAR
+#undef CLEAR_WSTRLIST
+}
+
+
+int
+_PyCoreConfig_Copy(_PyCoreConfig *config, const _PyCoreConfig *config2)
+{
+    _PyCoreConfig_Clear(config);
+
+#define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
+#define COPY_STR_ATTR(ATTR) \
+    do { \
+        if (config2->ATTR != NULL) { \
+            config->ATTR = _PyMem_RawWcsdup(config2->ATTR); \
+            if (config->ATTR == NULL) { \
+                return -1; \
+            } \
+        } \
+    } while (0)
+#define COPY_WSTRLIST(LEN, LIST) \
+    do { \
+        if (config2->LIST != NULL) { \
+            config->LIST = _Py_wstrlist_copy(config2->LEN, config2->LIST); \
+            if (config->LIST == NULL) { \
+                return -1; \
+            } \
+        } \
+        config->LEN = config2->LEN; \
+    } while (0)
+
+    COPY_ATTR(install_signal_handlers);
+    COPY_ATTR(use_environment);
+    COPY_ATTR(use_hash_seed);
+    COPY_ATTR(hash_seed);
+    COPY_ATTR(_install_importlib);
+    COPY_ATTR(allocator);
+    COPY_ATTR(dev_mode);
+    COPY_ATTR(faulthandler);
+    COPY_ATTR(tracemalloc);
+    COPY_ATTR(import_time);
+    COPY_ATTR(show_ref_count);
+    COPY_ATTR(show_alloc_count);
+    COPY_ATTR(dump_refs);
+    COPY_ATTR(malloc_stats);
+
+    COPY_ATTR(coerce_c_locale);
+    COPY_ATTR(coerce_c_locale_warn);
+    COPY_ATTR(utf8_mode);
+
+    COPY_STR_ATTR(pycache_prefix);
+    COPY_STR_ATTR(module_search_path_env);
+    COPY_STR_ATTR(home);
+    COPY_STR_ATTR(program_name);
+    COPY_STR_ATTR(program);
+
+    COPY_WSTRLIST(argc, argv);
+    COPY_WSTRLIST(nwarnoption, warnoptions);
+    COPY_WSTRLIST(nxoption, xoptions);
+    COPY_WSTRLIST(nmodule_search_path, module_search_paths);
+
+    COPY_STR_ATTR(executable);
+    COPY_STR_ATTR(prefix);
+    COPY_STR_ATTR(base_prefix);
+    COPY_STR_ATTR(exec_prefix);
+#ifdef MS_WINDOWS
+    COPY_STR_ATTR(dll_path);
+#endif
+    COPY_STR_ATTR(base_exec_prefix);
+
+    COPY_ATTR(isolated);
+    COPY_ATTR(site_import);
+    COPY_ATTR(bytes_warning);
+    COPY_ATTR(inspect);
+    COPY_ATTR(interactive);
+    COPY_ATTR(optimization_level);
+    COPY_ATTR(parser_debug);
+    COPY_ATTR(write_bytecode);
+    COPY_ATTR(verbose);
+    COPY_ATTR(quiet);
+    COPY_ATTR(user_site_directory);
+    COPY_ATTR(buffered_stdio);
+#ifdef MS_WINDOWS
+    COPY_ATTR(legacy_windows_fs_encoding);
+    COPY_ATTR(legacy_windows_stdio);
+#endif
+    COPY_ATTR(_check_hash_pycs_mode);
+    COPY_ATTR(_frozen);
+
+#undef COPY_ATTR
+#undef COPY_STR_ATTR
+#undef COPY_WSTRLIST
+    return 0;
+}
+
+
+const char*
+_PyCoreConfig_GetEnv(const _PyCoreConfig *config, const char *name)
+{
+    assert(config->use_environment >= 0);
+
+    if (!config->use_environment) {
+        return NULL;
+    }
+
+    const char *var = getenv(name);
+    if (var && var[0] != '\0') {
+        return var;
+    }
+    else {
+        return NULL;
+    }
+}
+
+
+int
+_PyCoreConfig_GetEnvDup(const _PyCoreConfig *config,
+                        wchar_t **dest,
+                        wchar_t *wname, char *name)
+{
+    assert(config->use_environment >= 0);
+
+    if (!config->use_environment) {
+        *dest = NULL;
+        return 0;
+    }
+
+#ifdef MS_WINDOWS
+    const wchar_t *var = _wgetenv(wname);
+    if (!var || var[0] == '\0') {
+        *dest = NULL;
+        return 0;
+    }
+
+    wchar_t *copy = _PyMem_RawWcsdup(var);
+    if (copy == NULL) {
+        return -1;
+    }
+
+    *dest = copy;
+#else
+    const char *var = getenv(name);
+    if (!var || var[0] == '\0') {
+        *dest = NULL;
+        return 0;
+    }
+
+    size_t len;
+    wchar_t *wvar = Py_DecodeLocale(var, &len);
+    if (!wvar) {
+        if (len == (size_t)-2) {
+            return -2;
+        }
+        else {
+            return -1;
+        }
+    }
+    *dest = wvar;
+#endif
+    return 0;
+}
+
+
+void
+_PyCoreConfig_GetGlobalConfig(_PyCoreConfig *config)
+{
+#define COPY_FLAG(ATTR, VALUE) \
+        if (config->ATTR == -1) { \
+            config->ATTR = VALUE; \
+        }
+#define COPY_NOT_FLAG(ATTR, VALUE) \
+        if (config->ATTR == -1) { \
+            config->ATTR = !(VALUE); \
+        }
+
+    COPY_FLAG(utf8_mode, Py_UTF8Mode);
+    COPY_FLAG(isolated, Py_IsolatedFlag);
+    COPY_FLAG(bytes_warning, Py_BytesWarningFlag);
+    COPY_FLAG(inspect, Py_InspectFlag);
+    COPY_FLAG(interactive, Py_InteractiveFlag);
+    COPY_FLAG(optimization_level, Py_OptimizeFlag);
+    COPY_FLAG(parser_debug, Py_DebugFlag);
+    COPY_FLAG(verbose, Py_VerboseFlag);
+    COPY_FLAG(quiet, Py_QuietFlag);
+#ifdef MS_WINDOWS
+    COPY_FLAG(legacy_windows_fs_encoding, Py_LegacyWindowsFSEncodingFlag);
+    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
+#endif
+    COPY_FLAG(_frozen, Py_FrozenFlag);
+
+    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
+    COPY_NOT_FLAG(buffered_stdio, Py_UnbufferedStdioFlag);
+    COPY_NOT_FLAG(site_import, Py_NoSiteFlag);
+    COPY_NOT_FLAG(write_bytecode, Py_DontWriteBytecodeFlag);
+    COPY_NOT_FLAG(user_site_directory, Py_NoUserSiteDirectory);
+
+    if (config->_check_hash_pycs_mode == NULL) {
+        config->_check_hash_pycs_mode = _Py_CheckHashBasedPycsMode;
+    }
+
+#undef COPY_FLAG
+#undef COPY_NOT_FLAG
+}
+
+
+/* Set Py_xxx global configuration variables from 'config' configuration. */
+void
+_PyCoreConfig_SetGlobalConfig(const _PyCoreConfig *config)
+{
+#define COPY_FLAG(ATTR, VAR) \
+        if (config->ATTR != -1) { \
+            VAR = config->ATTR; \
+        }
+#define COPY_NOT_FLAG(ATTR, VAR) \
+        if (config->ATTR != -1) { \
+            VAR = !config->ATTR; \
+        }
+
+    COPY_FLAG(utf8_mode, Py_UTF8Mode);
+    COPY_FLAG(isolated, Py_IsolatedFlag);
+    COPY_FLAG(bytes_warning, Py_BytesWarningFlag);
+    COPY_FLAG(inspect, Py_InspectFlag);
+    COPY_FLAG(interactive, Py_InteractiveFlag);
+    COPY_FLAG(optimization_level, Py_OptimizeFlag);
+    COPY_FLAG(parser_debug, Py_DebugFlag);
+    COPY_FLAG(verbose, Py_VerboseFlag);
+    COPY_FLAG(quiet, Py_QuietFlag);
+#ifdef MS_WINDOWS
+    COPY_FLAG(legacy_windows_fs_encoding, Py_LegacyWindowsFSEncodingFlag);
+    COPY_FLAG(legacy_windows_stdio, Py_LegacyWindowsStdioFlag);
+#endif
+
+    COPY_NOT_FLAG(use_environment, Py_IgnoreEnvironmentFlag);
+    COPY_NOT_FLAG(buffered_stdio, Py_UnbufferedStdioFlag);
+    COPY_NOT_FLAG(site_import, Py_NoSiteFlag);
+    COPY_NOT_FLAG(write_bytecode, Py_DontWriteBytecodeFlag);
+    COPY_NOT_FLAG(user_site_directory, Py_NoUserSiteDirectory);
+
+    if (config->_check_hash_pycs_mode != NULL) {
+        _Py_CheckHashBasedPycsMode = config->_check_hash_pycs_mode;
+    }
+
+    /* Random or non-zero hash seed */
+    Py_HashRandomizationFlag = (config->use_hash_seed == 0 ||
+                                config->hash_seed != 0);
+
+#undef COPY_FLAG
+#undef COPY_NOT_FLAG
+}
+
+
+/* Get the program name: use PYTHONEXECUTABLE and __PYVENV_LAUNCHER__
+   environment variables on macOS if available. */
+static _PyInitError
+config_init_program_name(_PyCoreConfig *config)
+{
+    /* If Py_SetProgramName() was called, use its value */
+    const wchar_t *program_name = _Py_path_config.program_name;
+    if (program_name != NULL) {
+        config->program_name = _PyMem_RawWcsdup(program_name);
+        if (config->program_name == NULL) {
+            return _Py_INIT_NO_MEMORY();
+        }
+        return _Py_INIT_OK();
+    }
+
+#ifdef __APPLE__
+    /* On MacOS X, when the Python interpreter is embedded in an
+       application bundle, it gets executed by a bootstrapping script
+       that does os.execve() with an argv[0] that's different from the
+       actual Python executable. This is needed to keep the Finder happy,
+       or rather, to work around Apple's overly strict requirements of
+       the process name. However, we still need a usable sys.executable,
+       so the actual executable path is passed in an environment variable.
+       See Lib/plat-mac/bundlebuiler.py for details about the bootstrap
+       script. */
+    const char *p = _PyCoreConfig_GetEnv(config, "PYTHONEXECUTABLE");
+    if (p != NULL) {
+        size_t len;
+        wchar_t* program_name = Py_DecodeLocale(p, &len);
+        if (program_name == NULL) {
+            return DECODE_LOCALE_ERR("PYTHONEXECUTABLE environment "
+                                     "variable", (Py_ssize_t)len);
+        }
+        config->program_name = program_name;
+        return _Py_INIT_OK();
+    }
+#ifdef WITH_NEXT_FRAMEWORK
+    else {
+        const char* pyvenv_launcher = getenv("__PYVENV_LAUNCHER__");
+        if (pyvenv_launcher && *pyvenv_launcher) {
+            /* Used by Mac/Tools/pythonw.c to forward
+             * the argv0 of the stub executable
+             */
+            size_t len;
+            wchar_t* program_name = Py_DecodeLocale(pyvenv_launcher, &len);
+            if (program_name == NULL) {
+                return DECODE_LOCALE_ERR("__PYVENV_LAUNCHER__ environment "
+                                         "variable", (Py_ssize_t)len);
+            }
+            config->program_name = program_name;
+            return _Py_INIT_OK();
+        }
+    }
+#endif   /* WITH_NEXT_FRAMEWORK */
+#endif   /* __APPLE__ */
+
+    /* Use argv[0] by default, if available */
+    if (config->program != NULL) {
+        config->program_name = _PyMem_RawWcsdup(config->program);
+        if (config->program_name == NULL) {
+            return _Py_INIT_NO_MEMORY();
+        }
+        return _Py_INIT_OK();
+    }
+
+    /* Last fall back: hardcoded string */
+#ifdef MS_WINDOWS
+    const wchar_t *default_program_name = L"python";
+#else
+    const wchar_t *default_program_name = L"python3";
+#endif
+    config->program_name = _PyMem_RawWcsdup(default_program_name);
+    if (config->program_name == NULL) {
+        return _Py_INIT_NO_MEMORY();
+    }
+    return _Py_INIT_OK();
+}
+
+
+static const wchar_t*
+config_get_xoption(const _PyCoreConfig *config, wchar_t *name)
+{
+    int nxoption = config->nxoption;
+    wchar_t **xoptions = config->xoptions;
+    for (int i=0; i < nxoption; i++) {
+        wchar_t *option = xoptions[i];
+        size_t len;
+        wchar_t *sep = wcschr(option, L'=');
+        if (sep != NULL) {
+            len = (sep - option);
+        }
+        else {
+            len = wcslen(option);
+        }
+        if (wcsncmp(option, name, len) == 0 && name[len] == L'\0') {
+            return option;
+        }
+    }
+    return NULL;
+}
+
+
+static _PyInitError
+config_init_home(_PyCoreConfig *config)
+{
+    wchar_t *home;
+
+    /* If Py_SetPythonHome() was called, use its value */
+    home = _Py_path_config.home;
+    if (home) {
+        config->home = _PyMem_RawWcsdup(home);
+        if (config->home == NULL) {
+            return _Py_INIT_NO_MEMORY();
+        }
+        return _Py_INIT_OK();
+    }
+
+    int res = _PyCoreConfig_GetEnvDup(config, &home,
+                                      L"PYTHONHOME", "PYTHONHOME");
+    if (res < 0) {
+        return DECODE_LOCALE_ERR("PYTHONHOME", res);
+    }
+    config->home = home;
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_hash_seed(_PyCoreConfig *config)
+{
+    const char *seed_text = _PyCoreConfig_GetEnv(config, "PYTHONHASHSEED");
+
+    Py_BUILD_ASSERT(sizeof(_Py_HashSecret_t) == sizeof(_Py_HashSecret.uc));
+    /* Convert a text seed to a numeric one */
+    if (seed_text && strcmp(seed_text, "random") != 0) {
+        const char *endptr = seed_text;
+        unsigned long seed;
+        errno = 0;
+        seed = strtoul(seed_text, (char **)&endptr, 10);
+        if (*endptr != '\0'
+            || seed > 4294967295UL
+            || (errno == ERANGE && seed == ULONG_MAX))
+        {
+            return _Py_INIT_USER_ERR("PYTHONHASHSEED must be \"random\" "
+                                     "or an integer in range [0; 4294967295]");
+        }
+        /* Use a specific hash */
+        config->use_hash_seed = 1;
+        config->hash_seed = seed;
+    }
+    else {
+        /* Use a random hash */
+        config->use_hash_seed = 0;
+        config->hash_seed = 0;
+    }
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_utf8_mode(_PyCoreConfig *config)
+{
+    const wchar_t *xopt = config_get_xoption(config, L"utf8");
+    if (xopt) {
+        wchar_t *sep = wcschr(xopt, L'=');
+        if (sep) {
+            xopt = sep + 1;
+            if (wcscmp(xopt, L"1") == 0) {
+                config->utf8_mode = 1;
+            }
+            else if (wcscmp(xopt, L"0") == 0) {
+                config->utf8_mode = 0;
+            }
+            else {
+                return _Py_INIT_USER_ERR("invalid -X utf8 option value");
+            }
+        }
+        else {
+            config->utf8_mode = 1;
+        }
+        return _Py_INIT_OK();
+    }
+
+    const char *opt = _PyCoreConfig_GetEnv(config, "PYTHONUTF8");
+    if (opt) {
+        if (strcmp(opt, "1") == 0) {
+            config->utf8_mode = 1;
+        }
+        else if (strcmp(opt, "0") == 0) {
+            config->utf8_mode = 0;
+        }
+        else {
+            return _Py_INIT_USER_ERR("invalid PYTHONUTF8 environment "
+                                     "variable value");
+        }
+        return _Py_INIT_OK();
+    }
+
+    return _Py_INIT_OK();
+}
+
+
+static int
+config_str_to_int(const char *str, int *result)
+{
+    const char *endptr = str;
+    errno = 0;
+    long value = strtol(str, (char **)&endptr, 10);
+    if (*endptr != '\0' || errno == ERANGE) {
+        return -1;
+    }
+    if (value < INT_MIN || value > INT_MAX) {
+        return -1;
+    }
+
+    *result = (int)value;
+    return 0;
+}
+
+
+static int
+config_wstr_to_int(const wchar_t *wstr, int *result)
+{
+    const wchar_t *endptr = wstr;
+    errno = 0;
+    long value = wcstol(wstr, (wchar_t **)&endptr, 10);
+    if (*endptr != '\0' || errno == ERANGE) {
+        return -1;
+    }
+    if (value < INT_MIN || value > INT_MAX) {
+        return -1;
+    }
+
+    *result = (int)value;
+    return 0;
+}
+
+
+static void
+get_env_flag(_PyCoreConfig *config, int *flag, const char *name)
+{
+    const char *var = _PyCoreConfig_GetEnv(config, name);
+    if (!var) {
+        return;
+    }
+    int value;
+    if (config_str_to_int(var, &value) < 0 || value < 0) {
+        /* PYTHONDEBUG=text and PYTHONDEBUG=-2 behave as PYTHONDEBUG=1 */
+        value = 1;
+    }
+    if (*flag < value) {
+        *flag = value;
+    }
+}
+
+
+static _PyInitError
+config_read_env_vars(_PyCoreConfig *config)
+{
+    assert(config->use_environment > 0);
+
+    /* Get environment variables */
+    get_env_flag(config, &config->parser_debug, "PYTHONDEBUG");
+    get_env_flag(config, &config->verbose, "PYTHONVERBOSE");
+    get_env_flag(config, &config->optimization_level, "PYTHONOPTIMIZE");
+    get_env_flag(config, &config->inspect, "PYTHONINSPECT");
+
+    int dont_write_bytecode = 0;
+    get_env_flag(config, &dont_write_bytecode, "PYTHONDONTWRITEBYTECODE");
+    if (dont_write_bytecode) {
+        config->write_bytecode = 0;
+    }
+
+    int no_user_site_directory = 0;
+    get_env_flag(config, &no_user_site_directory, "PYTHONNOUSERSITE");
+    if (no_user_site_directory) {
+        config->user_site_directory = 0;
+    }
+
+    int unbuffered_stdio = 0;
+    get_env_flag(config, &unbuffered_stdio, "PYTHONUNBUFFERED");
+    if (unbuffered_stdio) {
+        config->buffered_stdio = 0;
+    }
+
+#ifdef MS_WINDOWS
+    get_env_flag(config, &config->legacy_windows_fs_encoding,
+                 "PYTHONLEGACYWINDOWSFSENCODING");
+    get_env_flag(config, &config->legacy_windows_stdio,
+                 "PYTHONLEGACYWINDOWSSTDIO");
+#endif
+
+    if (config->allocator == NULL) {
+        config->allocator = _PyCoreConfig_GetEnv(config, "PYTHONMALLOC");
+    }
+
+    if (_PyCoreConfig_GetEnv(config, "PYTHONDUMPREFS")) {
+        config->dump_refs = 1;
+    }
+    if (_PyCoreConfig_GetEnv(config, "PYTHONMALLOCSTATS")) {
+        config->malloc_stats = 1;
+    }
+
+    const char *env = _PyCoreConfig_GetEnv(config, "PYTHONCOERCECLOCALE");
+    if (env) {
+        if (strcmp(env, "0") == 0) {
+            config->coerce_c_locale = 0;
+        }
+        else if (strcmp(env, "warn") == 0) {
+            config->coerce_c_locale_warn = 1;
+        }
+        else {
+            config->coerce_c_locale = 1;
+        }
+    }
+
+    wchar_t *path;
+    int res = _PyCoreConfig_GetEnvDup(config, &path,
+                                      L"PYTHONPATH", "PYTHONPATH");
+    if (res < 0) {
+        return DECODE_LOCALE_ERR("PYTHONPATH", res);
+    }
+    config->module_search_path_env = path;
+
+    if (config->use_hash_seed < 0) {
+        _PyInitError err = config_init_hash_seed(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_tracemalloc(_PyCoreConfig *config)
+{
+    int nframe;
+    int valid;
+
+    const char *env = _PyCoreConfig_GetEnv(config, "PYTHONTRACEMALLOC");
+    if (env) {
+        if (!config_str_to_int(env, &nframe)) {
+            valid = (nframe >= 0);
+        }
+        else {
+            valid = 0;
+        }
+        if (!valid) {
+            return _Py_INIT_USER_ERR("PYTHONTRACEMALLOC: invalid number "
+                                     "of frames");
+        }
+        config->tracemalloc = nframe;
+    }
+
+    const wchar_t *xoption = config_get_xoption(config, L"tracemalloc");
+    if (xoption) {
+        const wchar_t *sep = wcschr(xoption, L'=');
+        if (sep) {
+            if (!config_wstr_to_int(sep + 1, &nframe)) {
+                valid = (nframe >= 0);
+            }
+            else {
+                valid = 0;
+            }
+            if (!valid) {
+                return _Py_INIT_USER_ERR("-X tracemalloc=NFRAME: "
+                                         "invalid number of frames");
+            }
+        }
+        else {
+            /* -X tracemalloc behaves as -X tracemalloc=1 */
+            nframe = 1;
+        }
+        config->tracemalloc = nframe;
+    }
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_init_pycache_prefix(_PyCoreConfig *config)
+{
+    assert(config->pycache_prefix == NULL);
+
+    const wchar_t *xoption = config_get_xoption(config, L"pycache_prefix");
+    if (xoption) {
+        const wchar_t *sep = wcschr(xoption, L'=');
+        if (sep && wcslen(sep) > 1) {
+            config->pycache_prefix = _PyMem_RawWcsdup(sep + 1);
+            if (config->pycache_prefix == NULL) {
+                return _Py_INIT_NO_MEMORY();
+            }
+        }
+        else {
+            // -X pycache_prefix= can cancel the env var
+            config->pycache_prefix = NULL;
+        }
+    }
+    else {
+        wchar_t *env;
+        int res = _PyCoreConfig_GetEnvDup(config, &env,
+                                          L"PYTHONPYCACHEPREFIX",
+                                          "PYTHONPYCACHEPREFIX");
+        if (res < 0) {
+            return DECODE_LOCALE_ERR("PYTHONPYCACHEPREFIX", res);
+        }
+
+        if (env) {
+            config->pycache_prefix = env;
+        }
+    }
+    return _Py_INIT_OK();
+}
+
+
+static _PyInitError
+config_read_complex_options(_PyCoreConfig *config)
+{
+    /* More complex options configured by env var and -X option */
+    if (config->faulthandler < 0) {
+        if (_PyCoreConfig_GetEnv(config, "PYTHONFAULTHANDLER")
+           || config_get_xoption(config, L"faulthandler")) {
+            config->faulthandler = 1;
+        }
+    }
+    if (_PyCoreConfig_GetEnv(config, "PYTHONPROFILEIMPORTTIME")
+       || config_get_xoption(config, L"importtime")) {
+        config->import_time = 1;
+    }
+    if (config_get_xoption(config, L"dev" ) ||
+        _PyCoreConfig_GetEnv(config, "PYTHONDEVMODE"))
+    {
+        config->dev_mode = 1;
+    }
+
+    _PyInitError err;
+    if (config->tracemalloc < 0) {
+        err = config_init_tracemalloc(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    if (config->pycache_prefix == NULL) {
+        err = config_init_pycache_prefix(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+    return _Py_INIT_OK();
+}
+
+
+static void
+config_init_locale(_PyCoreConfig *config)
+{
+    if (config->utf8_mode >= 0 && config->coerce_c_locale >= 0) {
+        return;
+    }
+
+    if (_Py_LegacyLocaleDetected()) {
+        /* POSIX locale: enable C locale coercion and UTF-8 Mode */
+        if (config->utf8_mode < 0) {
+            config->utf8_mode = 1;
+        }
+        if (config->coerce_c_locale < 0) {
+            config->coerce_c_locale = 1;
+        }
+        return;
+    }
+}
+
+
+/* Read configuration settings from standard locations
+ *
+ * This function doesn't make any changes to the interpreter state - it
+ * merely populates any missing configuration settings. This allows an
+ * embedding application to completely override a config option by
+ * setting it before calling this function, or else modify the default
+ * setting before passing the fully populated config to Py_EndInitialization.
+ *
+ * More advanced selective initialization tricks are possible by calling
+ * this function multiple times with various preconfigured settings.
+ */
+
+_PyInitError
+_PyCoreConfig_Read(_PyCoreConfig *config)
+{
+    _PyInitError err;
+
+    _PyCoreConfig_GetGlobalConfig(config);
+
+    if (config->isolated > 0) {
+        config->use_environment = 0;
+        config->user_site_directory = 0;
+    }
+
+#ifdef MS_WINDOWS
+    if (config->legacy_windows_fs_encoding) {
+        config->utf8_mode = 0;
+    }
+#endif
+
+    assert(config->use_environment >= 0);
+    if (config->use_environment) {
+        err = config_read_env_vars(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    /* -X options */
+    if (config_get_xoption(config, L"showrefcount")) {
+        config->show_ref_count = 1;
+    }
+    if (config_get_xoption(config, L"showalloccount")) {
+        config->show_alloc_count = 1;
+    }
+
+    err = config_read_complex_options(config);
+    if (_Py_INIT_FAILED(err)) {
+        return err;
+    }
+
+    if (config->utf8_mode < 0) {
+        err = config_init_utf8_mode(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    if (config->home == NULL) {
+        err = config_init_home(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    if (config->program_name == NULL) {
+        err = config_init_program_name(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    config_init_locale(config);
+
+    if (config->_install_importlib) {
+        err = _PyCoreConfig_InitPathConfig(config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
+        }
+    }
+
+    /* default values */
+    if (config->dev_mode) {
+        if (config->faulthandler < 0) {
+            config->faulthandler = 1;
+        }
+        if (config->allocator == NULL) {
+            config->allocator = "debug";
+        }
+    }
+    if (config->use_hash_seed < 0) {
+        config->use_hash_seed = 0;
+        config->hash_seed = 0;
+    }
+    if (config->faulthandler < 0) {
+        config->faulthandler = 0;
+    }
+    if (config->tracemalloc < 0) {
+        config->tracemalloc = 0;
+    }
+    if (config->coerce_c_locale < 0) {
+        config->coerce_c_locale = 0;
+    }
+    if (config->utf8_mode < 0) {
+        config->utf8_mode = 0;
+    }
+    if (config->_frozen < 0) {
+        config->_frozen = 0;
+    }
+    if (config->argc < 0) {
+        config->argc = 0;
+    }
+
+    return _Py_INIT_OK();
+}
diff --git a/Python/import.c b/Python/import.c
index 3a59183..de132a3 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -2279,8 +2279,6 @@
     NULL
 };
 
-const char *_Py_CheckHashBasedPycsMode = "default";
-
 PyMODINIT_FUNC
 PyInit__imp(void)
 {
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 63f461a..95fb861 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -108,28 +108,6 @@
     return _PyRuntime.finalizing != NULL;
 }
 
-/* Global configuration variable declarations are in pydebug.h */
-/* XXX (ncoghlan): move those declarations to pylifecycle.h? */
-int Py_DebugFlag = 0; /* Needed by parser.c */
-int Py_VerboseFlag = 0; /* Needed by import.c */
-int Py_QuietFlag = 0; /* Needed by sysmodule.c */
-int Py_InteractiveFlag = 0; /* Needed by Py_FdIsInteractive() below */
-int Py_InspectFlag = 0; /* Needed to determine whether to exit at SystemExit */
-int Py_OptimizeFlag = 0; /* Needed by compile.c */
-int Py_NoSiteFlag = 0; /* Suppress 'import site' */
-int Py_BytesWarningFlag = 0; /* Warn on str(bytes) and str(buffer) */
-int Py_FrozenFlag = 0; /* Needed by getpath.c */
-int Py_IgnoreEnvironmentFlag = 0; /* e.g. PYTHONPATH, PYTHONHOME */
-int Py_DontWriteBytecodeFlag = 0; /* Suppress writing bytecode files (*.pyc) */
-int Py_NoUserSiteDirectory = 0; /* for -s and site.py */
-int Py_UnbufferedStdioFlag = 0; /* Unbuffered binary std{in,out,err} */
-int Py_HashRandomizationFlag = 0; /* for -R and PYTHONHASHSEED */
-int Py_IsolatedFlag = 0; /* for -I, isolate from user's env */
-#ifdef MS_WINDOWS
-int Py_LegacyWindowsFSEncodingFlag = 0; /* Uses mbcs instead of utf-8 */
-int Py_LegacyWindowsStdioFlag = 0; /* Uses FileIO instead of WindowsConsoleIO */
-#endif
-
 /* Hack to force loading of object files */
 int (*_PyOS_mystrnicmp_hack)(const char *, const char *, Py_ssize_t) = \
     PyOS_mystrnicmp; /* Python/pystrcmp.o */